The invention relates to a braking device that can be released electromagnetically, in accordance with the preamble to claim 1.
Braking devices that can be released electromagnetically, particularly spring-loaded brakes, serve to brake static and dynamic loads and to hold them in place. In the case of braking devices intended to brake rotational movement, the spring-loaded brake is usually installed directly on the drive motor. Spring-loaded brakes of this kind are used, e.g., in drive technology to rapidly brake electromotors powering loads or flywheel masses when the current is cut off. In the case of braking devices that can be released electromagnetically, a magnet system is used to release the spring-loaded brake, which [in German] is also called xe2x80x9cairingxe2x80x9d the brake. By allowing current to run to the coil of the magnet system an armature is electromagnetically moved against to the force of the brake spring, in order to thereby release the drive for subsequent motion. When current to the coil is cut off, the armature no longer works against the force of the brake spring due to the absence of magnetic force, with the result that the brake spring presses a brake shoe against a braking surface, e.g., a brake disk or rail, thus producing the braking moment needed to stop the drive and lock it.
The size of this kind of electromagnetically released braking device is basically determined by the magnitude of the braking moment or force that is required, since the magnet system of the braking device must be able to overcome the force of the brake spring exerted during the release process, i.e., when the brake shoe is lifted from the braking surface.
The invention is based on the problem of creating an braking device released electromagnetically that can produce a large braking force or braking moment in a device of limited size.
The invention solves this problem with a braking device that exhibits the features of claim 1.
Advantageous embodiments of the invention are indicated in the secondary claims.
In accordance with the invention the braking force produced by the one or more brake springs is diverted by at least one pressure element to diagonal wedge areas and is transmitted in reinforced form to at least one brake shoe. The armature of the magnet system basically acts on the pressure element in the direction of the brake spring. The effect is that the braking force or braking moment is greater than the spring force of the brake spring, while the magnet system for releasing the brake must overcome only the slighter spring force of the brake spring. Thus a weaker magnet system, with its correspondingly smaller size, can be used even when the braking force is greater.
With the selection of the angle of the diagonal wedge area, which determines the deflection or enhancement of force, it is possible to optimally utilize the maximum possible spring energy of the brake springs and to accommodate the structural specifications of the braking device.
Ideally the magnet system will be overexcited at the beginning of the release process, while the armature is in motion; after the armature reaches its terminal position operation is switched to nominal excitation. The result is that the brake is very quickly released and can be kept in released state with reduced power.